if vs. whether (If she comes or not is not important.)

[Minh]

Hi everyone,

In the noun clause, the phrases "if...or not" and "whether... or not" have the same funtional in English sentence. For example:
1) "I wonder if she will come or not." = 2)" I wonder whether she will come or not."

However, when these phrases are subjects of the sentence, they are not equivalent. For example:
3) Whether she comes or not is not important.(This sentence is ok.)
4) If she comes or not is not important. This sentence is not acceptable. Can anyone tell me why it is not ok in this case?

Many thanks,
Minh

[Mister Micawber]

.
#4 is acceptable, but #3 is preferred.
.
_________________
Native English teacher at Mister Micawber's

[Minh]

Hi Mr. Micawber,
In the context of the folowing sentences,
1) If a person is prompt is important to our boss.
2) Whether or not a person is prompt is important to our boss.
#1 sentence makes common sense to me because in #2 it has a negative part of the person who is not prompt. I wonder why a person is not prompt is important to the boss. What kind of the boss he is!
The answer is #2 which is chosen over the #1.

Thanks,
Minh

[Mister Micawber]

.
The negative part is not relevant.
Whether (or not) one is prompt = If one is prompt or not = Promptness.

If a person is prompt (or not) is important to our boss.
Whether or not a person is prompt is important to our boss.
Promptness is important to our boss.

With a clause used as a subject, the whether form is preferred to the if form.
.
_________________
Native English teacher at Mister Micawber's

[Minh]

Thank you Mr. Micawber. Your explanation leads me to have another curiosity. Why is the part "or not" added to follow to the words "whether" and "if" when they really have no meanings?

Thanks

Minh

[Mister Micawber]

.
I think it is for emphasis that there are two options. I avoid it myself, but it is common enough.
.
_________________
Native English teacher at Mister Micawber's